1. Field of the Invention
The present invention relates to a ground rod having an induction discharge skin-effect plate, and in particular to a ground rod having an induction discharge skin-effect plate in which an electric current inputted into a ground rod can be easily discharged to the ground by forming an induction discharge skin-effect plate in parallel with a ground rod at a certain interval and increasing a critical surface area when a thunderbolt falls. In addition, an electric potential increase of the ground can be lowered by allowing an electric potential discharge to take place between the upper and lower vertical portions of a ground rod and an induction discharge skin-effect plate when a thunderbolt falls.
2. Description of the Background Art
Generally, a ground rod is a facility which is designed to protect all kinds of electric and electronic instruments and facilities such as a power generator, a transformer, a reactor, a cable and a GIS bus and a man and beast each having a non-self restoring insulation from an over voltage which generates at an electric system. In an area where thundercloud, which may induce a thunderbolt, approaches, atmosphere air is ionized by an electric potential difference between thundercloud and ground. In addition, an ion having an opposite polarity corresponding to an ion in the atmosphere at a higher part of the ground increases. When the thundercloud increases, the ions are discharged by a corona effect at the higher part.
With the above principles, a lightening rod is installed at the top of a building. A corona discharge is formed through a rising top of the lightening rod when thundercloud increases, so that the ions are discharged for thereby inducing a thunderbolt.
Since the thunderbolt electric current induced by the lightening rod contains a high frequency component, it is needed to fast discharge through the ground. However, a ground impedance increases by an inherent resistance of the ground when a thunderbolt electric current is discharged to the ground through a ground rod, and a ground electric potential increases, so that an electric potential, which is applied to a protected instrument such as a large power facility instrument, a communication and weak electric current facility and an architectural facility, increases for thereby damaging the above facilities.
So as to overcome the above problems, as shown in FIG. 1, there is provided a Korean patent registration number 0339924 (arc induction type needle ground rod). In a ground rod which is connected with a protected instrument and is buried under the ground for thereby preventing a protected instrument installed on the ground from an insulation damage and erroneous operation by a thunderbolt electric current, the arc induction type needle ground rod comprises a ground rod which has an upper end connected with the protected instrument and a needle holder by which a needle is fixed movably in a circumferential direction so that arc can be easily generated when a surge voltage is supplied, a discharge tube which increases a ground resistance by increasing the surface area of a ground pole with respect to a commercial frequency failure electric current and maintains a zero electric potential based on a contact with the ground with respect to a surge-based high frequency failure electric current and receives and electrically insulates the ground rod so that arc can be easily generated at the needle, and an arc induction type coil which has one end connected with a lower side of the ground rod and the other end connected with a lower side of the discharge tube for thereby providing a path up to the discharge tube with respect to a commercial frequency failure electric current and induces a generation of arc by providing an electric potential difference between the needle and the discharge tube with respect to the surge-based high frequency failure electric current.
However, according to the needle ground rod of the Korean paten registration number 0339924, since a thunderbolt is applied through only the surface of the ground rod by a skin effect by a high frequency electric current when a thunderbolt falls, so that a resistance inductance causes many problems.